It is known that calcium and iron compounds can be added to coal based fuels to function as so-called sulfur scavengers. For example, U.S. Pat. No. C 4,302,207 describes fuels based on coal which contain calcium oxide, calcium carbonate, organic calcium salts, iron oxide, iron carboxylate, etc., in addition to organic or inorganic binders. The fuels produced in this way can be burned as such or converted to a lump form, e.g., by extrusion.
In production of finely divided fuels based on coal of the type described initially an especially fine distribution of the iron and calcium compounds in the fuel is especially important in order to effectively reduce the sulfur dioxide content of the offgases. With the processes known in the past such a fine distribution could not be achieved at all or could be achieved only inadequately due to the dry mixing of additives containing iron and calcium. The process according to this invention is based on the elimination of this disadvantage.